textproduct: Rapid City

KEY MESSAGES

- A cold front will move slowly across western South Dakota tonight, bringing overnight chances of thunderstorms.

- Cooler Monday, then hot again Tuesday.

- Slight chance for storms Monday, with higher chances for storms Tuesday night and Wednesday.

UPDATE

Issued at 923 PM MDT Sun Jun 7 2026

The main event this evening was the supercell crossing Butte/Harding/Perkins counties, which produced gusts up to 70 mph before exiting the forecast area. Surface obs show a cold front now crossing Harding County through portions of NE WY. Gusts across NE WY have been reaching above 50 mph at times behind the front. These winds, though not as strong, will continue crossing the CWA over the next few hours. A secondary line of storms have develop just ahead of the frontal boundary across Harding/Butte/Perkins counties, extending southward toward Rapid City. Most of these storms will produce gusty winds up to 50 mph and large amounts of small hail. Nevertheless, will join the neighbors with extending the Severe Thunderstorm Watch until 06z and cancel as storms progress E/NE.

DISCUSSION

(This Afternoon Through Saturday) Issued at 1143 AM MDT Sun Jun 7 2026

Upper level analysis has a low over Alberta with a trough extending through the northern Rockies into the Desert Southwest. At the surface there is an area of low pressure over western North Dakota. A cold front extends southward from the low along the Montana/South Dakota border, into northeastern Wyoming, and down into northern Utah. This cold front will be the focus for convection later today.

Thunderstorms will form early this afternoon over northeastern Wyoming and move northeastward through the evening. Steep lapse rates, SB CAPE of 1500-2000 J/kg, and 0-6 km shear is 30-40 kts, indicates the possibility of severe storms later today and into the evening. However, the more favorable parameters for severe storms will likely be located further north - closer to the Montana/North Dakota border. As the potential for severe storms wane by late evening, scattered showers and storms will continue overnight across much of western South Dakota behind the cold front.

On Monday, it will be cooler with highs in the 70s to low 80s. Surface high pressure will slide through the CWA, resulting in increasing southeasterly winds of 15-25 mph during the afternoon over the northeastern Wyoming and far western South Dakota plains. Another hot day is ahead on Tuesday with prefrontal warming and gusty southerly winds. Highs will be back in the 90s. Due to the greenness from the recent rain, the NBM high temperatures are most likely a few degrees too high. Another cold front will move through the area late Tuesday and Wednesday, resulting in a chance for scattered storms, some of which may be severe closer to central South Dakota. Temperatures for the second half of the week will be closer to seasonal averages.

AVIATION

(For the 06Z TAFS Through 06Z Monday Night) Issued At 1047 PM MDT Sun Jun 7 2026

Isolated thunderstorms will dissipate overnight across western and central South Dakota. And area of MVFR CIGS will affect portions of the NE WY plains over the next few hours but should exit the forecast area by 09z. However, MVFR/IFR CIGS may linger across the Black Hills until after sunrise. A cold front crossing the area overnight will bring gusty winds of 40kt+. Then winds will quickly decrease Monday morning. VFR conditions are also expected Monday.

UNR WATCHES/WARNINGS/ADVISORIES

SD...None. WY...None.